MOSCOW, June 19 (Reuters) - Russian energy giant Gazprom is fighting numerous legal cases, with combined claims of at least 17 billion euros from European companies, according to Reuters calculations.

Gazprom has launched counter proceedings at Russia's St Petersburg and Leningrad Region Arbitration Court, threatening the European counterparties with fines if they continue litigation outside Russia.

Following are several key legal cases:

RUSSIAN COURT PROCEEDINGS

* The court banned French company Engie and Czech's Innogy Energie from pursuing international arbitration against Gazprom on June 19.

* The court ruling on May 22 banned Austrian energy company OMV Gas Marketing and Trading GmbH from pursuing arbitration proceedings in Stockholm against the exporting arm of Gazprom.

* Gazprom filed claims on May 17 against French company Engie, Czech company Innogy Energie and Swiss DXT Commodities at the St. Petersburg court, seeking ban on international arbitrations, according to the court.

* Gazprom lodged a claim of more than $900 million against Polish companies in the St Petersburg court. Gazprom is seeking compensation of $710 million and 886.4 million zlotys ($224.70 million) from Europol GAZ SA, Orlen SA, Ernst and Young Global Ltd, and Ernst and Young sp z oo Corporate Finance.

* According to the Russian court, Czech firm Net4Gas (N4G) would have to pay a fine of around 112.96 million euros ($122.7 million) unless it drops a lawsuit against Gazprom over missed payments.

* In November 2023, the same court said Poland's Europol Gaz will have to pay a fine of around $1.57 billion if it continues to pursue a 6 billion zloty ($1.51 billion) lawsuit against Gazprom in Sweden.

* Gazprom has lodged similar claims with the court against Germany's Uniper Global Commodities SE and Metha-Methanhandel GmbH, Dutch Gasunie Transport Service, Ukraine's Naftogas, Poland's Orlen, and ZSE Energia from Slovakia.

* In March, the court ruled to ban Uniper from international arbitration, threatening with a fine of 14.3 billion euros.

INTERNATIONAL LITIGATIONS

* German utility Uniper won a multi-billion euro arbitration last week against former long-time supplier Gazprom, allowing it to tear up dormant gas supply contracts and potentially setting a precedent for similar cases.

* An International Chamber of Commerce (ICC) tribunal has prohibited Gazprom from continuing with Russian legal proceedings against CEZ on May 24. In turn, the St. Petersburg court banned CEZ from seeking international arbitration.

* OMV said on May 22 that gas supplies from Gazprom may be suspended in connection with a foreign court ruling, without identifying the case, but assuring the market it would have replacement cover.

* Bulgarian state gas company Bulgargaz EAD sought to sue Gazprom for 400 million euros ($435 million) for breaking a gas supply contract.

* Greek gas supplier DEPA Commercial filed for arbitration to seek a price revision on its gas supply contract with Gazprom.

* The owner of the Polish section of the Yamal gas pipeline, Europol Gaz, was pursuing a claim of about 6 billion zlotys ($1.45 billion) against Gazprom, according to Poland's State Assets Minister in May 2023.

* Dutch firm BBL Company V.O.F opened up arbitration proceedings in the Netherlands in April 2023 against Gazprom Exports, seeking compensation over unused gas pipeline capacity bookings.

* Net4Gas has decided to start arbitration proceedings against a major Russian gas supplier over missed payments in April 2023. Net4Gas did not identify the supplier, but a government minister has said that the Czech company did not receive payments from Gazprom.

* OMV lodged a claim against Gazprom in Stockholm arbitration, seeking compensation of 575.3 million euros over a gas contract.

* France's Engie launched arbitration proceedings against Gazprom in February 2023 claiming the Russian company had failed to meet its gas supply obligations. Engie also started arbitration in Stockholm over gas prices in January 2022, while Gazprom launched a counterclaim in April that year.

* German energy firm RWE initiated arbitration proceedings against Gazprom in November 2022 over missing gas deliveries.

* Polish company PGNiG (now PKN Orlen) launched arbitration in March 2022 over payments for gas.

* Ukrainian energy firm Naftogaz launched arbitration proceedings in September 2022 against Gazprom over Russian natural gas transit to Europe.

Naftogaz said in June 2023, it had taken legal action in the United States against Russia to recover $5 billion awarded in the Hague as compensation for damages and lost property in Crimea. Italy's Eni started arbitration in May 2022 over Russia's demand to pay for gas exports using the rouble.

* Finland's state-owned energy provider Gasum in May 2022 said it would take its dispute over rouble payments with Gazprom Export to arbitration proceedings. Gazprom Export said in November 2022 an arbitration court in Stockholm had ruled that Gasum must pay Gazprom more than 300 million euros ($326.82 million) for gas supplies after failing to stick to its take-or-pay obligations.

($1 = 0.9219 euros) (Reporting by Oksana Kobzeva and Vladimir Soldatkin; Editing by Shinjini Ganguli)